This invention relates to a method of processing light-sensitive silver halide photographic materials, more particularly to a method of processing light-sensitive silver halide photographic materials which enables use of a stabilizing solution stably over a long term by controlling the sulfite ion concentration in the stabilizing solution.
Generally speaking, light-sensitive silver halide photographic materials subjected to imagewise exposure are processed according to various processing steps to form images thereon. For example, processing may be conducted following the steps of color developing--bleach-fixing--water washing or color developing--bleaching--fixing--water washing or developing--fixing--water washing.
Whereas, in recent years, for the purpose of conservation of environment, insurance of water resource or reduction in cost, there have been made various proposals to reduce washing water which has been employed in a large amount to a great extent. Above all, a multi-stage countercurrent stabilizing processing technique as disclosed in Japanese Unexamined Patent Publication No. 8543/1982 or a processing technique with the use of a stabilizing solution containing a bismuth complex as disclosed in Japanese Unexamined Patent Publication No. 134636/1983 has been known.
These processing techniques with stabilizing solutions may be appreciated as epoch-making methods in that the water washing processing step can be substantially obviated and further that stability of the dye image after processing can be increased.
Stabilizing processing is performed subsequent to the step using a processing solution having fixing ability such as a fixing solution or a bleach-fixing solution, and generally practiced in a plurality of tanks and according to the counter-current method, while supplementing a stabilizing solution from the final tank. Also, as different from the water washing processing step in which soluble residual matters are thoroughly washed away, stabilizing processing permits a certain amount of processing liquor components in the preceding bath to be brought about into the stabilizing processing step by the light-sensitive silver halide photographic material and accumulated therein. Of course, the amount of the stabilizing solution brought about by the light-sensitive silver halide photographic material is controlled in order to maintain the processing solution components in the preceding bath at a level within a certain range.
However, as mentioned above, as different from the water washing processing which removes thoroughly the soluble processing liquor components with a large amount of water, stabilizing processing will readily ensue various problems. For example, there may be involved generation of mold or scale due to prolonged residence time of the stabilizing solution, soluble silver complexes brought about by a processing solution having fixing ability (fixing solution or bleach-fixing solution), generation (sulfiding) of sulfur and silver sulfide due to decomposition of silver thiosulfate in most cases.
Above all, generation of sulfur or silver sulfide gives a vital damage to the dye image. For example, when sulfur or silver sulfide is formed in processing of a light-sensitive silver halide photographic material, particularly in the processing step of color nega, sulfur or silver sulfide will be incorporated into the gelatin on the surface of the light-sensitive silver halide photographic material, whereby serious problems in photographic performance may be caused such as loss of commercial value by frequent occurrence of so called white drop-out portions during printing, etc.
Accordingly, overcoming of the above problems must be said to be imminent and important in practical application of the stabilizing processing.
Heretofore, sulfites have frequently been used for preventing decomposition of thiosulfates or silver thiosulfate complexes in fixing solutions or bleach-fixing solutions, but it is also effective to use sulfites in stabilizing solutions for preventing decomposition of thiosulfates or silver thiosulfate complexes. As the method for incorporating a sulfite in a stabilizing solution, one may think of the method in which a large amount of a sulfite is incorporated in a processing solution such as fixing solution or bleach-fixing solution in the preceding bath brought about by the light-sensitive silver halide photograhic material or the method in which a sulfite is incorporated in the replenisher solution for the stabilizing solution.
However, in the case of the former method, since the fixing solution or bleach-fixing solution containing a sulfite brought about by the light-sensitive silver halide photographic material is generally diluted to 1/2-1/1000 fold in the case of the multi-stage countercurrent stabilizing processing, the sulfite concentration is lower as the processing bath is later, and therefore sulfiding will readily occur when the stabilizing solution resided over a long term. On the other hand, in the case of processing a small amount, because no sulfite is supplied into the stabilizing processing bath at all, the same problem as described above may be caused. Further, when a large amount of a sulfite is added to a bleach-fixing solution, the reduction reaction of an organic acid ferric complex with a sulfite occurs, resulting in problems such as formation of a leuco derivative or deterioration of desilverization.
On the other hand, in the latter case when a sulfite is incorporated in the replenisher solution for stabilizing solution, if the amount of the light-sensitive silver halide photographic material processed is small, the sulfurous acid will be deteriorated because the sulfite is little supplemented, whereby sulfiding occurs similarly as in the former case. On the contrary, if the days with large amount of processing continue and the sulfite is supplemented in an excessive amount to the stabilizing processing bath, there will be caused inconveniences such that mold or bacteria will be readily generated when the bath is left to stand for several days, etc.
Thus, it has been very difficult according to the method of the prior art to maintain and control over a long term a stabilizing solution which is effectively prevented from sulfiding and yet is small in generation of mold or bacteria.
As for bleach-fixing solution, a method for detecting sulfite ions is known, but this method cannot be easily practiced by anybody for detection of sulfite ions, but some steps are required to be operated following the operation procedures for detection of sulfite ions and operations must be done carefully.